ANATOMY & PHYSIOLOGY TISSUES

ANATOMY & PHYSIOLOGYTISSUESTISSUESgroup of similar cells specialized to perform a specific function

Tissues: 4 TypesEpithelialConnectiveMuscleNervous Epithelial Tissue (Epithelium)the lining, covering, and glandular tissue of the body

Functions:ProtectionSecretionAbsorptionFiltration

Characteristic of Epitheliumcells close together, some connected by cell junctionstop layer exposed to exterior of body or inside of cavity (apical layer)lower surface connected to a Basement Membrane (BM)is avascular (no direct blood supply)able to regenerate if well nourishedClassification of Epitheliumsimple1 layer cellsstratified>1 layer cells

Shape Classification of EpitheliumSquamousfried-egg shape

cuboidalcube-shape

Shape Classification of Epitheliumcolumnartall, rectangular shapeName the shape:

Simple EpitheliumFunctions:AbsorptionSecretionFiltration Simple Squamous Epitheliumthin layer squamous cells resting on BMcells close together (think floor tiles)forms membranes where filtration or rapid diffusion necessary (lungs, kidneys)forms serous membranes or serosa : moist, shiny membranes that line ventral body cavities and covers organ in themSimple Squamous Epithelium

Simple Cuboidal Epithelium1 layer cuboidal cells on BMfound in glands, ducts, kidney tubules, covers ovaries

SimpleColumnar Epithelium1 layer columnar cells packed closely togetherinterspersed with Goblet Cells which make & release mucuslines GI tract from stomach anusforms mucosae (mucous membranes) that line body cavities open to exterior of bodySimple Columnar Epithelium

Pseudostratified Columnar Epitheliumappears to have multiple layers but only has 1all cells attached to BM but not all cells reach apical surface (top)mainly does absorption & secretion2 varieties:Ciliatedin lining of tracheaNonciliated Pseudostratified Ciliated Columnar Epithelium

Pseudostratified Nonciliated Columnar Epithelium

Stratified Epithelium>1 layer of cells, epithelium named for shape of top layermore durable than simple epitheliumprimary function is protectionStratified Squamous Epithelium#1 stratified epithelium in body2 varieties:keratinizednonkeratinized Keratin: tough, insoluble protein found in hair, nails, & epidermisStratified Squamous Epitheliumkeratinizednonkeratinized

Stratified Cuboidal Epithelium2 or more layers with top layer cuboidal

Transitional Epitheliumtransitions from 1 shape to anotherfound in urinary bladder, ureters, urethrawhen vol of urine high epitheliumis stretched and epithelium looks like squamous cellswhen vol of urine low cells appear dome-shaped, cuboidalTransitional Epithelium

Stratified Columnar Epitheliumfound in salivary ducts

Connective Tissue (CT)connects thingsis everywhere in body#1 tissue type for amount and distributionConnective Tissue Characteristicsmost CT well vascularizedexcept:ligaments, tendons poor blood supplycartilage is avascularmake extracellular matrix (in varying amounts)Extracellular Matrix2 main elements:structureless ground substancewater adhesive proteins (glues everything together)charged polysaccharides (trap water) control viscosity of the CTfiberscollagen: #1 protein in bodyelasticreticularExtracellular Matrix

Connective Tissues Functionsprotectionsupportbinding substances togetherabsorption of large amounts of water (ground substance)Types of Connective TissuesBoneCartilageDense CTLoose CTBlood Boneaka osseous tissuefew cells surrounded by hard matrixcalcium saltsdue to its hardness has exceptional ability to protect & supportBone

Cartilagemore flexible than bone(also not as hard)Types:Hyaline Cartilagematrix is glassy, blue-whitefound: ends of long bones, larynx, fetal skeletonElastic Cartilageexternal earFibrocartilagevery compressible, forms discs in vertebral columnHyaline Cartilage

Dense CTmatrix: collagen fibers main ingredient + fibroblasts (make collagen)function: strengthfound: tendonsattach muscle to boneLigamentsconnect bone to bone

Dense CTLigaments:Tendons:

Loose CTsofter, more cellular, fewer fibers than most other CTTypes:Areolar CTAdipose TissueReticular CT

Areolar CTcobwebbydiffusely distributed thru out bodylayer under all mucous membranes (lamina propria)Functions:cushions & protectsholds things togetherreservoir of water (where water held when injured area becomes edematous)Areolar CT

Adipose Tissueaka fatadipocytes =fat cellssignet ringfound : subcutaneous layer beneath skinaround kidneys, eyeballs

Adipose Tissue

Reticular CTreticular cells which make reticular fibers (finer than collagen)forms: stroma: internal framework that supports ie. Stroma in lymph nodes support lymphocytesReticular CT

Blood blood cells in fluid matrix (plasma)Function:carries nutrients, gases, wastes, hormones etc. to/from cellsPlasma:fibers: soluble proteins become visible during blood clotting

Blood Cells

Muscle Tissuespecialized to contract produce motioncells called muscle fibersTypes:SkeletalCardiacSmooth Skeletal Musclestriated & voluntarymost attached to bonescontraction causes bone to move

Cardiac Musclestriated, involuntaryfound only in the heartcardiac muscle fibers have gaps between them (called intercalated discs) so conduction of nerve impulse is quicker

Cardiac Muscle Tissue

Smooth Muscle Tissueno striations, involuntaryfound: w/in tubes &hollow organs, irisperistalsis: contractions of smooth muscle w/in esophagus large intestine Smooth Muscle Tissue

Nervous Tissuefound in brain, spinal cord, nervesnerve cells called neuronsirritability & conductivity neurons receive & conduct nerve impulses Neurogliacells that support neuronsastrocytesoligodendrocytesependymal cellsmicrogliaSchwann cellssatellite cellsNervous Tissue

Wound HealingInflammation:nonspecific, generalized response aimed at preventing further injuryImmune Response:specific response aimed at specific invader

Wound Healing Regenerationreplacement of destroyed tissue by same cellsrepair appears like normal tissueFibrosis repair by dense, fibrous CT

?Regeneration or Fibrosis?type of tissueseverity of injury3 Stages of Tissue InjuryLeaky Capillariesclotting proteins enter injured area & form clot bleeding stops & clot holds edges of wound togetherclot protects injured area from contamination(infection, dirt)clot dries scab

Clot Formation

2. Granulation Tissue Formsis a delicate pink tissuemostly capillaries (friable)contains phagocytes (eat up clot & fibroblasts that synthesize collagen which forms scar)

Granulation Tissue

3. Surface epithelium regenerates grows from edges centerscar depends on depth & severity of woundRegeneration varies by tissue typeRegeneration goes well in epithelial tissues and fibrous CT & boneMuscle regenerates poorlyNervous tissue replaced by scar tissue

Embryonic Development of Tissues3 primary germ layers formed from the inner cell mass of a blastocyst (7-14 days after fertilization)

3 Primary Germ LayersEctoderm nervous system & epidermisEndoderm mucosa & glandsMesoderm everything else

22 day embryo

Normal Aging Processuncertain what causes aging process to startchemical or environmental insultsaging clock

Tissue Changes with AgingEpithelial: membranes thin, skin less elastic, glands secrete lessCT: bones porous, tissue repair slowerMuscle Tissue: muscles atrophyNervous Tissue: nervous tissue atrophies